Diaphragm pump

ABSTRACT

A diaphragm pump comprises a housing, a motor supported by the housing, a drive assembly operably connected to the motor and a wobble plate operably connected to the drive assembly. The motor includes a drive shaft defining a rotational axis. The wobble plate orbits about the rotational axis of the drive shaft. The drive assembly includes a reduction gear assembly and a drive member connected to the gear assembly. The gear assembly provides a predetermined gear reduction to reduce the speed of the motor and increase the torque needed to drive the pump.

CROSS REFERENCE TO RELATED APPLICATIONS

The present application claims priority from U.S. Provisional PatentApplication Ser. No. 611082,370 filed Jul. 21, 2008; which provisionalpatent application is expressly incorporated herein by reference, in itsentirety.

BACKGROUND

Exemplary embodiments herein relate to a diaphragm pump for a hydraulicsystem. Diaphragm pumps possess many advantages and are widely used.Generally, the diaphragm pump defines a variable volume chamber by usinga space between a pump casing and a diaphragm, which is controlled by awobble plate. Typically, the wobble plate, driven by a shaft, operatesto lift away from and then compress against the diaphragm in a wavelikeor peristaltic motion. An inlet and an outlet are provided through thepump casing with one-way valves for preventing backflow. These cooperatewith the diaphragm to create an appropriate variable pumping chamberwith a peristaltic action. The conventional diaphragm pumps require arelatively large motor to generate the torque needed to drive the pump.However, the use of the large motors increases the weight, size and costof the diaphragm pumps.

An improved diaphragm pump is provided which employs a relativelysmaller, lighter and more cost effective motor and drive assembly whichcan produce equivalent speed and torque as the previously used largermotors.

BRIEF DESCRIPTION

According to one aspect, a diaphragm pump comprises a housing, a motorsupported by the housing, a drive assembly operably connected to themotor and a wobble plate operably connected to the drive assembly. Themotor includes a drive shaft defining a rotational axis. The wobbleplate orbits about the rotational axis of the drive shaft. The driveassembly includes a reduction gear assembly and a drive member connectedto the gear assembly. The gear assembly provides a predetermined gearreduction to reduce the speed of the motor and increase the torqueneeded to drive the pump.

According to another aspect, a diaphragm pump comprises a housing and agenerally small, lightweight motor supported by the housing. The motorincludes a drive shaft defining a rotational axis. A drive assembly isoperably connected to the motor. The drive assembly includes a reductiongear assembly including a planetary gear train having a plurality ofcompound gears and a ring gear. A wobble plate is rotatably connected tothe gear assembly. The wobble plate orbits about the rotational axis ofthe drive shaft. The gear assembly provides a predetermined gearreduction to reduce the speed of the motor and increase the torqueneeded to drive the pump.

According to yet another aspect, a diaphragm pump comprises a housingand a permanent magnet motor supported by the housing. The motorincludes a drive shaft defining a rotational axis. A drive assembly ispositioned within the housing and is operably connected to the motor.The drive assembly includes a reduction gear assembly for reducing thespeed and increasing the torque of the permanent magnet motor needed todrive the pump. The gear assembly includes a planetary gear traincomprised of a plurality of drive gears and a stationary ring gear.Rotation of the drive shaft causes the plurality of drive gears torotate about the ring gear. A drive member is rotatably connected to thereduction gear assembly. A wobble plate is rotatably connected to thedrive member.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side perspective view of a diaphragm pump with a portionthereof removed according to the present disclosure.

FIG. 2 is a side elevational view of the diaphragm pump of FIG. 1.

FIG. 3 is an exploded perspective view of the diaphragm pump of FIG. 1.

FIGS. 4-6 are enlarged perspective views of the illustrated componentsof the diaphragm pump of FIG. 3.

FIG. 7 is a partial cross-sectional view of the diaphragm pump of FIG.1.

DETAILED DESCRIPTION

It should, of course, be understood that the description and drawingsherein are merely illustrative and that various modifications andchanges can be made in the structures disclosed without departing fromthe present disclosure. It will also be appreciated that the variousidentified components of the diaphragm pump disclosed herein are merelyterms of art that may vary from one manufacturer to another and shouldnot be deemed to limit the present disclosure. All references todirection and position, unless otherwise indicated, refer to theorientation of the diaphragm pump illustrated in the drawings and shouldnot be construed as limiting the claims appended hereto.

Referring now to drawings, wherein like numerals refer to like partsthroughout the several views, a diaphragm pump 100 according to thepresent disclosure is illustrated. With reference to FIGS. 1-3 and 7,the diaphragm pump 100 comprises a housing 102, a motor 104 supported bythe housing, a drive assembly 106 operably connected to the motor and awobble or swash plate 108 operably connected to the drive assembly. Thehousing 102, which houses the drive assembly 106, includes a firsthousing part 112, an intermediate, second housing part 114, and a thirdhousing part 116.

As shown in FIGS. 3 and 4, the first housing part 112 includes a firstenclosure 120 supported on a suitable base 122. The first enclosure 120includes a generally cylindrical shaped wall 124 having an outer surface126 and an inner surface 128, and a back wall 130. The inner surfaceincludes a plurality of circumferentially spaced first notches 140 andsecond notches 142. The first and second notches are generally U-shapedand extend axially on the inner surface 128, an end of each notch beingspaced from the end wall 130. As will be discussed in greater detailbelow, the second notches 142, which can be slightly larger than thefirst notches, serve as guides to properly align the first and secondhousing parts 112 and 114. Located on the wall 124 are a pair of tabs146 having openings 148 which are dimensioned to receive fasteners (notshown). A suitable fastener is shown in FIG. 7.

With continued reference to FIG. 4, the base 122 includes a centermember 160 having a front wall 162 and a rear wall 164 and opposed sidewalls 166 and 168. The front wall is generally flush with an end 170 ofthe first enclosure 120 and includes openings 172 dimensioned to receivefasteners. The rear wall 164 is spaced from the back wall 130. A topsurface 174 of the center member includes an upwardly extending shelf176 that spans from the rear wall 164 to the back wall 130 and has a topsurface 178 configured to support the motor 104. First and secondflanges 184 and 186 extend from the respective side walls 166 and 168.Each flange includes mounting holes 188 which allow the base 122 to bemounted to a subjacent flat surface.

With reference now to FIG. 5, the second housing part 114 includes asecond enclosure 200 having a generally cylindrical shaped wall 202 anda vertical wall 204 located within the enclosure. The wall 202 includesan outer surface 206 and an inner surface 208. A flange 210 extendsoutwardly from a first end portion 212 of the wall 202. The flangeincludes a plurality of circumferentially spaced first projections 220and second projections 222. The first and second projections 220, 222are generally U-shaped and are dimensioned to be received in therespective first and second notches 140, 142 of the first housing part112. Located on the wall 202 are spaced apart first bosses 230 havingopenings (not shown). Spaced apart second bosses 236 having openings 238are disposed on the inner surface 208 of the wall 202. Ends 240 of thesecond bosses 236 project from a second end portion 242 of the wall 202.

The vertical wall 204, which separates the second enclosure 200 into afirst portion 250 and a second portion 252, includes an opening 260. Agenerally circular flange 262 is secured to the wall 204 and extendsinto the second portion 252. The flange 262 includes an outer wall 264and an inner wall 266. The inner wall defines an opening 270 having anaxis which is coincident with an axis defined by the wall opening 260.The opening 270 is dimensioned to receive a first bearing 272. At leastone support 274 is provided for the flange 262. The support is connectedto the wall 204 and spans between the inner surface 208 of the wall 202and the outer surface 264 of the flange 262. As shown, three spacedapart supports 274 are provided for the flange 262; although, this isnot required.

With reference to FIG. 7, the third housing part 116 includes a thirdenclosure 290 having fluid inlet section (not shown) and a fluid outletsection (not shown). An inlet valve 292 is operably connected to theinlet section and an outlet valve 294 is operably connected to theoutlet section. The third enclosure at least partially defines a pumpchamber 296. Located on a wall 300 of the third enclosure are tabs 302having openings 304 which are dimensioned to receive fasteners F.

To secure the second housing part 114 to the first housing part 112, thefirst and second projections 220, 222 are aligned with the first andsecond notches 140, 142. Once properly aligned, the projections can beat least partially slidingly received in the notches. In this position,the openings of the first bosses register with the openings 148 of thetabs 142 and the openings 172 of the base 122. Fasteners (not shown)extend through the openings 148, 172 and threadingly engage the bossopenings. To secure the third housing part 116 to the second housingpart 114, the openings 304 of the tabs 302 are aligned with the openings238 of the second bosses 236. The fasteners F extend through the tabopenings 304 and threadingly engage the boss openings 238.

With reference again to FIGS. 3 and 4, the motor 104, which can be arelatively small, lightweight permanent magnet motor, includes a motorhousing 320, a power switch or connection to the power source 322located on the housing and an output or drive shaft 324. The powersource can be alternating current or direct current batteries or a cableattached to a dc power source, like a motor vehicle battery. The atleast one battery can have, for a non-limiting example, a voltage in therange of about 6 to around 42 volts. The watt rating for the motor canbe for a non-limiting example in the range of 1 to 500. The output shaftof the motor defines a longitudinal axis. As indicated above, the motor104 can be supported on the shelf 176 of the base 122. The output shaftextends through an opening (not visible) located on the wall 130 of thefirst housing part 112 (see FIG. 2). With additional reference to FIG.6, the drive assembly 106 can comprise a reduction gear assembly 340 anda drive member 342 operably coupled to the reduction gear assembly. Inthe depicted embodiment, the reduction gear assembly is a planetary geartrain including a spur gear 350, a plurality of compound gears 352 and aring gear 354. The spur gear is mounted to an end portion 358 of themotor output shaft 324 which projects through the opening of the wall130. Each compound gear 352 includes a first gear 360 and a smallersecond gear 362. An axis of rotation of the first gear is coincidentwith an axis of rotation of the second gear. The second gear 362 is atleast partially surrounded by the first gear 360; although, this is notrequired. For each compound gear 352, a portion of the second gear 362extends outwardly from the first gear 360 to engage the ring gear 354.

The ring gear 354 includes a wall 370 having an outer surface 372 and aninner surface 374. The inner surface defines an opening 376. The innersurface includes a plurality of circumferentially spaced teeth 378configured to simultaneously engage the second gears 362. Thisconfiguration provides for a compact gear assembly. The outer surfaceincludes a plurality of circumferentially spaced first projections 380and second, larger projections 382. The first and second projections380, 382 engage the first and second projection 220, 222. Particularly,the first and second projections 380, 382 are dimensioned to be receivedin respective recesses (not visible) formed by the generally U-shapedfirst and second projections 220, 222 of the second housing part 114.Once positioned within the recesses, the ring gear 354 is non-rotatablysecured to the second housing part 114.

The drive member 342 comprises a base 390 and a shaft 392 extendingoutwardly from a central raised portion 394 of the base. The base isgenerally triangular in shape; although, it should be appreciated thatalternative shapes for the base are contemplated. To some extent, theshape of the base 390 would be dependent on the number of compound gears352 in the gear assembly 340. The base is dimensioned to be rotatablypositioned within the opening 376 of the ring gear and includes posts396 which extend from corner sections 398 of the base. Each post 396extends through an opening 400 of each compound gear 352 tonon-rotatably secure the compound gear 352 to the drive member 342. Inthe assembled condition, the compound gears are spaced from each otherso that the spur gear 350 can simultaneously engage the first gears 360.The raised portion 394 is received in the opening 260 of the wall 204.The shaft 392 defines a longitudinal axis which is coincident with therotational axis of the drive shaft 324. The shaft 392 extends through anopening 406 of the first bearing 272 (see FIG. 5) and includes a keyedsection 410. As shown in FIG. 5, a coupling 420 is secured to the shaftkeyed section. The coupling can be generally mushroom shaped andincludes a head 422, a post 424 projecting from the head, and an opening426 for receiving the shaft 392. The post 424 is sized to befrictionally received within the bearing opening 406. Once positionedwith the opening, the head 422 engages a surface of the bearing.

With reference to FIG. 7, housed within the third housing part 116 isthe wobble plate 108. The wobble plate is rotated by the shaft 392 ofthe drive member 342, which is, in turn, rotated by the drive shaft 324of the motor 104. A plurality of pistons (only one piston 440 is shown)are reciprocated by the wobble plate 108. The piston 440 is attached toa diaphragm 442 which provides an internal seal for the pump. The pistonreciprocates within the pump chamber 296 that is at least partiallydefined by a manifold plate 450. The manifold plate includes the one-wayinlet valve 292 that allows water to flow into the pump chamber and theone-way outlet valve 294 that allows water to flow out of the pumpchamber.

The wobble plate 108 is coupled to a rocker arm 460 by a second bearing462. The wobble plate provides an inclined and radially offset mountingfor the second bearing. The second bearing defines the normal centralaxis of the wobble plate. This normal central axis of the wobble plate108 is angularly displaced about 3° to 6° from the rotational axis ofthe shaft 392. The wobble plate has a surface 466 which cooperates withthe first bearing 272 to move the rocker arm in a reciprocating motionin response to a rotation of the shaft 392. The pistons are attached tothe rocker arm 460 by a plurality of screws 470. The pistons are locatedsymmetrically about the drive shaft and swing about a radial arcrelative to the drive shaft centerline. The swinging motion of thepistons cause the outer portion of the diaphragm 442 to move a greaterdistance than the inner portion of the diaphragm.

In use, rotation of the motor drive shaft 324 causes the spur gear 350secured thereto to simultaneously engage the first gears 360 of thecompound gears 352. Rotation of the first gears rotates the second gears362 within the ring gear 354. The gear assembly provides a predeterminedgear reduction (for example, a 13.8:1 gear reduction) to reduce thespeed of the drive shaft 324 thereby allowing the smaller, lighter andmore cost effective motor 104 to generate the increased torque needed todrive the diaphragm pump 100. As the compound gears 352 rotate, theshaft 392 of the drive member 342 rotates about the axis of the driveshaft 324. The drive shaft, in turn, engages the wobble plate 108 whichreciprocates the pistons 440. During an intake stroke, the volume of thepump chamber 296 increases and draws in water through the inlet sectionand inlet valve 292. During the power stroke, the piston pushes thewater out of the pump chamber and through the outlet valve 294 andoutlet section. The cycle is repeated as the output shaft 392 rotatesthe wobble plate 108.

The housing 102, drive member 342 and coupling 420 can be made of asuitable metal or polymeric material. The diaphragm can be made of asuitable flexible, resilient material, which can be a polymeric materialor an elastomer.

It will be appreciated that various of the above-disclosed and otherfeatures and functions, or alternatives thereof, may be desirablycombined into many other different systems or applications. Also variouspresently unforeseen or unanticipated alternatives, modifications,variations or improvements therein may be subsequently made by thoseskilled in the art. It is intended that all of these, or equivalentsthereof are encompassed by the following claims.

1. A diaphragm pump comprising: a housing; a motor supported by thehousing, the motor including a drive shaft defining a rotational axis; adrive assembly operably connected to the motor, the drive assemblyincluding a reduction gear assembly and a wobble plate rotatablyconnected to the gear assembly, the wobble plate orbiting about therotational axis of the drive shaft; and wherein the gear assemblyprovides a predetermined gear reduction to reduce the speed of the motorand increase the torque needed to drive the pump.
 2. The diaphragm pumpof claim 1, wherein the reduction gear assembly comprises a planetarygear train.
 3. The diaphragm pump of claim 2, wherein the planetary geartrain includes a plurality of compound gears and a ring gear, the ringgear at least partially surrounding the plurality of compound gearsproviding for a compact reduction gear assembly.
 4. The diaphragm pumpof claim 3, wherein the reduction gear assembly further comprises a spurgear coupled to the drive shaft of the motor, each compound gearincluding a first gear and a second smaller diameter gear, the spur gearsimultaneously engaging the first gears of the plurality of compoundgears.
 5. The diaphragm pump of claim 4, wherein the ring gear includesa wall having an outer surface and an inner surface, the inner surfaceincluding a plurality of circumferentially spaced teeth configured tosimultaneously engage the second gears of the plurality of compoundgears.
 6. The diaphragm pump of claim 3, wherein the ring gear isnon-rotatably secured to the housing.
 7. The diaphragm pump of claim 3,wherein the drive assembly further includes a separate drive memberrotatably coupled to the housing and located between the reduction gearassembly and wobble plate.
 8. The diaphragm pump of claim 7, wherein thedrive member is at least partially positioned within the ring gear. 9.The diaphragm pump of claim 7, wherein the drive member includes a base,a first outwardly extending shaft for engaging the wobble plate and aplurality of second outwardly extending shafts, each compound gearsbeing non-rotatably secured to one of the second shafts.
 10. Thediaphragm pump of claim 9, wherein the first shaft of the drive memberdefines a longitudinal axis which is coincident with the rotational axisof the drive shaft and each second shaft of the drive member defines alongitudinal axis offset from and parallel to the rotational axis of thedrive shaft.
 11. The diaphragm pump of claim 9, wherein the secondshafts extend in a direction opposite to the direction that the firstshaft extends.
 12. The diaphragm pump of claim 1, wherein the reductiongear assembly provides about a 14:1 gear reduction to reduce the speedof the drive shaft thereby allowing the motor to generate increasedtorque needed to drive the diaphragm pump.
 13. A diaphragm pumpcomprising: a housing; a generally small, lightweight motor supported bythe housing, the motor including a drive shaft defining a rotationalaxis; a drive assembly operably connected to the motor, the driveassembly including: a reduction gear assembly including a planetary geartrain having a plurality of compound gears and a ring gear, and a wobbleplate rotatably connected to the gear assembly, the wobble plateorbiting about the rotational axis of the drive shaft; and wherein thegear assembly provides a predetermined gear reduction to reduce thespeed of the motor and increase the torque needed to drive the pump. 14.The diaphragm pump of claim 13, wherein the housing includes a firsthousing part and a second housing part releasably connected to the firsthousing part, the first and second housing parts together defining achamber for housing the reduction gear assembly.
 15. The diaphragm pumpof claim 14, wherein the ring gear is non-rotatably secured to one ofthe first housing part and the second housing part, the ring gearincluding an inner surface configured to engage the plurality ofcompound gears allowing rotation of the plurality of compound gearsabout the inner surface of the ring gear.
 16. The diaphragm pump ofclaim 15, wherein the reduction gear assembly further comprises a spurgear coupled to the drive shaft of the motor for simultaneously engagingthe plurality of compound gears.
 17. The diaphragm pump of claim 14,wherein the drive assembly further includes a separate drive memberrotatably coupled to both the reduction gear assembly and wobble plate,the drive member being at least partially positioned within the ringgear.
 18. The diaphragm pump of claim 13, wherein the motor is apermanent magnet motor and the reduction gear assembly provides about a14:1 gear reduction to reduce the speed of the drive shaft therebyallowing the permanent magnet motor to generate increased torque neededto drive the diaphragm pump.
 19. A diaphragm pump comprising: a housing;a permanent magnet motor supported by the housing, the motor including adrive shaft defining a rotational axis; a drive assembly positionedwithin the housing and operably connected to the motor, the driveassembly including: a reduction gear assembly for reducing the speed andincreasing the torque of the permanent magnet motor needed to drive thepump, the gear assembly including a planetary gear train comprised of aplurality of drive gears and a stationary ring gear, a rotation of thedrive shaft causing the plurality of drive gears to rotate about thering gear, a drive member rotatably connected to the reduction gearassembly, and a wobble plate rotatably connected to the drive member.20. The diaphragm pump of claim 19, wherein each drive gear includes afirst gear and a second gear, the first gears being simultaneouslyengaged by the drive shaft, the second gears being mounted to the drivemember and simultaneously engaging the ring gear.